This work presents recent developments on the influence of capillarity during impregnation of afibrous preform for LCM processes. In order to evaluate preform impregnation, saturated andunsaturated permeability tests are commonly carried out. This work highlights the influence of capillary effects during impregnation, considering the effect of liquid, fabric and fiber volume fraction choice. In order to take into account those capillary effects, a definition of capillary pressure was introduced. Tests of capillary wicking were performed and models accounting of swelling for natural fabrics weredeveloped. Results on capillary pressure estimation are relevant for a better understanding of impregnation during LCM processes and they could be inserted into numerical models of voids prediction